Yeah, they're blocked and the reason why they're close together is that there's no space in the Troc... that and you can network play jubeat together so you can play the same song at the same time.
And speaking of video and pics:
YouTube - uBeat - Scatman
This is my friend Josh playing Scatman and in the back you can see my other friend Richard playing another song. This was our collective first time to play uBeat... well, except for Richard, who had a lot of practise in Japan. ;p